Exhaust silencer for internalcombustion engines



9, 1950 E. E. BRYANT 2,520,756

EXHAUST SILENCER FOR INTERNAL-COMBUSTION ENGINES Filed Dec. 3, 1945 2Sheets-Sheet 1 G 0 0 w Y\ c m I 0 0 A 0 9 1 0% BY \y/ wZ flu wy,

Aug. 29, 1950 E. E. BRYANT 5 3 EXHAUST SILENCER FOR INTERNAL-COMBUSTIONENGINES Filed Dec. 3. 1945 2 Sheets-Sheet 2 9 e e eeeeeeeva 99a:

0 o o o o Q O Q9OOOOOOOOOOOQOOGQOOOOOOOO 0 o OOQO ee eee eee V INVENTOR.lwuMTZ Q/Zf Patented Aug. 29, 1950 EXHAUST SILENCER FOR INTERNAL-COMBUSTION ENGINES Edwin E. Bryant, Stoughton, Wis, assignor to NelsonMuffler Corporation, Stoughton, Wis, a corporation of WisconsinApplication December 3, 1945, Serial N 0. 632,297 8 Claims. (01. 181-57) This invention relates to engine exhaust silencers, and moreparticularly to a device of improved construction and improved operatingcharacteristics adapted to eliminate the noise from the exhaust ofinternal combustion engines of all types. It is desirable in most typesof internal combustion engines for maximum efficiency to keep backpressure at a minimum in the exhaust system. Mufilers which depend uponbaffling and giving the exhaust gases a circuitous path following thestructures of the prior art, frequently tend to increase back pressurebeyond desired limits.

One object of the present invention is to provide a strongly and.rigidly constructed, simple, and readily assembled silencer for theexhaust of internal combustion engines.

Another object of this invention is to provide an improved silencerwhich will efiect a high degree of quieting with a minimum amount ofback pressure. I

Another object of this invention is to provide an improved muffler whichis more efficient in operation, effects better heat dissipation, andproduces a more effective out of phasing of the exhaust pulsations.

Still another object of this invention is to provide a constructionwhich will minimize the danger of muiiler failure due to the explosionof unburnt gases, by allowing the built up pressures under suchconditions to dissipate readily.

Other and. further objects of the invention will appear from thefollowing description.

' In the accompanying drawings, which form part of the instantspecification and which are to be read in conjunction therewith, certainpreferred structural embodiments are set forth, in which like referencenumerals are used to indicate like'parts in the various views.

Fig. 1 is a perspective view of the exterior of a mufller constructed inaccordance with one preferred form and embodying this invention;

Fig. 2 is a longitudinal sectional View of the structure of Fig. 1 on anenlarged scale and taken along the line Z2 thereof;

Fig. 3 is a transverse sectional view taken along the line 3--3 of Fig.2;

Fig. 4 is a transverse sectional view taken along the line E l of Fig.2; a

Fig. 5 is an exterior elevation on a small scale of a muffler assemblyconstructed according to this invention in a modified form;

Fig. 6 is a longitudinal sectional view of one of the elements of thecombination shown in Fig. 5;.

Fig. 7 is a longitudinal sectional View of another of the elements shownin the combination of Fig. 5;

Fig. 8 is a transverse sectional view taken along the line 8-8 of Fig.6; and

Fig. 9 is a transverse sectional view taken along the line 9-9 of Fig. 7

In general, the present invention provides an improved arrangement ofparts in a muflier structure, providing a plurality of paths of travelfor the exhaust gases arranged to produce a maximum out of phasing ofthe exhaust pulsations with a minimum of back pressure. The severalpaths of travel are of different length and are so arranged relative toeach other that an efi'ective interference of both sound and pressureWaves Will result.

More particularly stated, the exhaust gases are first introduced into arelatively large chamber, and then dissipated and divided for travelalong a plurality of paths, the fiow along at least one of said pathsthen being further divided and dissipated in a manner so as to effectout of phasing. The means providing the plurality of paths of travel forthe exhaust gases are also of large area so that a minimum increase ofback pressure is obtained, the travel paths being unobstructed to allowthe ready dissipation of the exhaust pressures and prevent the buildingup of back pressure within the muffler structure.

The invention further provides an arrangement of parts for effecting amaximum reduction and dissipation of heat.

The exhaust gases may be discharged into the mufiier chamber parallel tothe axis thereof, or at right angles to the axis thereof, and if desireda plurality of mufiiers embodying the invention may be connected inseries.

More particularly, referring now to the drawings, Figs. 1-4, a shell Iof any suitable construction is provided with a pair of end walls 2 and3. Within the shell there is provided a partition 4 dividing the spacewithin the shell i into two chambers 5 and 6 of unequal size. Aplurality of openings '5 are provided in the partition 4 so thatcommunication exists between the chambers 5 and 5.

The exhaust gases are discharged into the larger chamber 6 through animperiorate inlet pipe 8,

the exhaust being delivered to the outer end 9 of the pipe -8 from theengine. The inner end Ill of the pipe 8 discharges into the largechamber 6. It will be observed that the inlet pipe 8, passing betweenend partition 3 and partition 4, Strengthens the assembly and acts as asupport for partition 4 which is tack welded or otherwise fastened tothe shell I by means of a flange portion ll. Also, the partition 4firmly holds the tube 8, acting with the end wall 3 to provide a firmand strong and vibration resistant mounting for the tube.

Extending from partition 2 through partition 4 into the smaller chamber5, there is provided a perforated tube l2 having a large number ofperforations I 3. The tube I2 is connected with a tube [4 which passesto the atmosphere .or connects with a pipe leading to atmosphere.

It will be observed that the pipe I2 is rigidly supported by thepartition 2 and the partition 4, a strong tube support thus beingprovided. Tube [2 also cooperates with the pipe 8 to strengthen theassembly. There is thus provided by the construction a very rigidassembly which is resistant to vibration. The tube 8 may be made ofrelatively thick and special heat resisting metal if necessary ordesired. It will be seen that the general construction provides a verlarge area for heat radiation and a large chamber for expansion coolingso that the exhaust gases may be cooled as they expand directly into thelarge chamber 6 from the inlet tube 8.

The original pulse is discharged from pipe 8 into chamber 6 whichcommunicates through holes I with the chamber of different size 5, thesize of the chambers and 6 and the communicating means I being such thatmaximum dissonance is obtained. Some of the exhaust gas will pass fromchamber 6 to chamber -5 whereas other portions of the gas will passdirectly from chamber 6 to the interior of the perforated tube l2through the openings l3. Some of the exhaust gases entering chamber 5will likewise pass directly into the tube l2 through the opening l3within chamber 5, whereas other gases will pass into the tube end, andmay also react against the end wall 3. In this manner a large number ofpaths of different lengths of travel for the exhaust gases are provided,the paths being arranged to cause cancellation of the pulses by thedifierence in the phase relationships.

The sum of the area of the perforations 13 may be larger than thcross-sectional area of the pipe Hi. This reduces back pressure of themuflier to a minimum and contributes to the efficiency of the structure.Similarly, there is a large vent area in the event of explosion ofunburned gases, which tends to reduce possibility of rupture to themuffler. Then, too, the balancing of pressures on both sides of thepartition 4 likewise minimizes the possibility of damage from explosion.

Referring now to Fig. 6, it will be observed that the same basicprinciples present in the construction just described are provided. Theexhaust gases are introduced into the larger chamber 6 through a pipe l5which extends at right angles to a perforated pipe 16. The exhaust isalso introduced through pipe 18 into a chamber l9 formed by animperforate partition 20 and the end partition 3. The partition 4 whichdivides the shell i into the larger chamber 6 and the smaller chamber 5is provided in this instance with a largeopening 2| instead of apluralit of smaller openings 1. The same principles governing aplurality of paths of differing lengths to the outlet pipe .6 areprovided in order to produce varying phase relations in the sound wavesand pressure pulsations which thus tend to cancel each other and producea minimum of sound as well as a slowing down of the veloci y of. t gaspulsations. The two chambers 5 and B produce a maximum dissonance. Againa minimum of back pressure is presented and th principles heretoforediscussed apply.

In Fig. 7 there is shown a mufiler substantially the same as that shownin Fig. 2 with the exception that the exhaust gases are introducedthrough pipe 22 into the larger chamber 6 at right angles to the axis ofthe mufller. Then, too, a larg opening 2] is provided in the partition 4instead of a plurality of smaller openings 1 such as shown in Fig. 2.There is a greater difference in size between the small chamber 5 andthe large chamber 6. The optimum positioning of the partition 4 whichdetermines the relative sizes of the small chamber and the large chamberdepends upon the type of internal combustion engine which is beingmuffled.

In order to get even more complete muting, two of the mufllers of thisinvention may be connected in-series. This is shown by Fig. 5 in whichthe two mufilers of Figs. 6 and 7 having side introduction of exhaustgases are connected in series by means of a clamp 23, the end 24 ofperforated pipe 5 being adapted to telescope within pipe 22.

t will be seen that the invention accomplishes its objects, due to thefact that there are multiple paths of travel for the gases so arrangedas to cause controlled interference between both the sound and gaspressure waves, reducing their intensity. In this connection it will beunderstood that the size and number of the openings in the centralpartition plate may be varied in accordance with the proportioning ofthe cooperative parts, whereby to produce the desired results.

The different impedances of the various paths of travel for the gasesproduce out of phasing, but without physical restriction of the gases intheir movements, whereby to minimize back pressure and also minimize thedanger of damage to the structure in the event of explosion.

The inlet of the exhaust gases into a large expansion chamber effects asubstantial temperature drop in the gases and a structure which effectsready heat dissipation. The structure is simple and easy to assemble,yet rigid and strong throughout.

The use of the plurality of chambers of different size, separated by apartition having openings therethrough of controlled size, and incombination with a perforated exhaust tubing results in the interferenceof the sound and pressure waves, as stated, reducing the intensity andvelocity of the gas pulsations at the mulller outlet.

It will be understood that certain features and sub-combinations of thestructures set forth are of utility and may be employed withoutreference to other features and sub-combinations. This is contemplatedby and is within the scope of the claims. It is further obvious thatvarious changes may be made in details within the scope of the claimsWithout departing from the spirit of the invention. It is, therefore, tobe understood that this invention is not to be limited to the specificdetails shown and described.

The invention is hereby claimed as follows:

1. An exhaust silencer comprising an elongated tubular shell closed atits opposite ends, a transverse partition within the shell dividing theshell into a plurality of longitudinally spaced'cham bers, saidpartition being perforated to provide gas passage means therethrough ofpredetermined siz'e, an inlet pipe extending through the 5 inlet end ofthe shell and through said partition and having an open end exhaustinginto the chamber adjacent the exhaust end of the shell,

an exhaust pipe extending through the exhaust end of the shell andthrough said partition and having an open end opening into the chamberadjacent the inlet end of the shell, said exhaust pipe being perforatedalong its length within both said chambers, said pipes and saidperforated partition comprising the complete gas transfer means withinthe shell.

2. An exhaust silencer comprising a tubular shell closed at its oppositeends, a transverse partition within the shell dividing the shell into aplurality of longitudinally spaced chambers, said partition beingperforated to provide gas passage means therethrough, an inlet pipeextending through one end of the shell and through said partition, saidpipe having an imperforate peripheral Wall and an open end exhaustinginto the chamber adjacent the end of the shell opposite the inlet to theshell, an exhaust pipe extending through said opposite end of the shelland through said partition, said exhaust pipe having an open end openinginto the chamber adjacent the inlet of said shell and being perforatedalong its length within both of said chambers, said pipes and saidperforated partition comprising the complete gas transfe means withinthe shell.

3. An exhaust silencer as in claim 2 in which the chamber adjacent theinlet to said shell is smaller than the chamber adjacent the outlet ofsaid shell.

4. An exhaust silencer comprising an elongated tubular shell closed atits opposite ends, a transverse partition within the shell and dividingthe same into a plurality of longitudinally spaced chambers, saidpartition being perforated to provide gas passage means therethrough ofpredetermined size, an exhaust pipe extending through the exhaust end ofthe shell and through said partition and having an open end opening intothe chamber adjacent the inlet end of the shell,

said exhaust pipe being perforated along its length within both saidchambers, an imperferate inlet pipe having its inner open end exhaustinginto the chamber adjacent the exhaust end of the shell and providingwith said exhaust pipe and said perforated partition a complete gastransfer means within the shell.

5. An exhaust silencer as claimed in claim 4, wherein there is provideda second partition subdividing the chamber remote from the exhaust endof the shell and wherein said perforated exhaust pipe opens through saidsecond partition into the adjacent end subdivision of the subdividedchamber.

6. An exhaust silencer as claimed in claim 5, wherein conduit means areprovided for introducing a portion of the gases to be silenced into thesaid end subdivision of the subdivided chamher.

7 An exhaust silencer as claimed in claim 6, wherein the conduit meansis disposed at substantially right angles to the axis of the exhaustpipe.

8. An exhaust silencer as claimed in claim 4,

.. wherein the inlet pipe is disposed at substantially right angles tothe axis of the exhaust pipe.

EDWIN E. BRYANT.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,447,688 ReedMar. 6, 1923 1,739,039 Powell Dec. 10, 1929 2,144,725 Manning Jan. 24,1939 2,150,768 Hedrick Mar. 14, 1939 2,182,204 Hector Dec. 5, 19392,186,062 Berg et a1 Jan. 9, 1940 2,194,550 Hector et a1 Mar, 26, 19402,235,705 Haas et a1 Mar. 18, 1941 2,357,791 Powers Sept. 5, 19442,382,159 Klemm Aug. 14, 1945

